Chaos Descending wrote:
No, of course those sources are not "canon", besides the root question isn't even worth contemplating.
What physical law of the universe could possibly have prevented the Death Star from shooting at non-planets?
Well it really wouldn't be a problem with physical laws that would have hypothetically kept the first one from destroying smaller targets, but rather design of the super laser. The Emperor may have decided it was cheaper just to make one that can only blow up planets (also remeber it seemed only one guy at the Death Star meeting in A New Hope was really worried about the Rebels and even that guy though the Rebels taking the Death Star out so arrogence may have had a hand in it) and decided the cost was worth it in the second one since the Rebels were able to blow up the first.